This invention relates to the art of automatic assembly of parts, and more particularly to a new and improved automated assembly system and method utilizing a programmable or flexible fixture and assembly cell.
One area of use of the present invention is in the automated assembly and manufacture of air frame subassemblies, although the principles of the present invention can be variously applied. It would be highly desirable to provide an automated manufacturing assembly cell for processing multi-dimensional and multi-configuration subassemblies utilizing computer controlled automatic fastening systems. It would be an advanced technology, automated material accountability and manufacturing assembly cell with the ability to process multi-configured and dimensional assemblies, using automatic fastening systems and a flexible or programmable holding fixture. Advantages would include the proven benefits of computer aided manufacturing along with flexible fastening and welding initiated through robotic processing using CAD/CAM data bases for repeatable close tolerance subassembly production including high quality drilling, fastening, sealant application, accurate dimensional repeatability of interfacing surfaces and maximum manufacturing-production flexibility for scheduling and lot sizing.
In manufacture of airframe subassemblies, part families under consideration include assemblies such as wing ribs, leading and trailing edge ribs on the wings and on the horizontal and vertical stabilizers, horizontal and vertical stabilizer ribs, body panels, fuselage frames, floor beams and miscellaneous subassemblies. The definition of a family would be any configuration of assemblies which remain relatively the same, one to the other, with variations in length, width and/or height. The assemblies would be similar in profile. A good example of the foregoing would be a wing rib. The wing rib at the root of the wing and the tip of the wing are basically the same configuration, an airfoil. They vary only in length, width and height, when compared to one another. These assemblies would then be considered an entire family.
In manufacture of assemblies including a family of parts, use of conventional static fixtures requiring a separate fixture for each assembly can be burdensome. For example, a typical number of different leading edge ribs on a tapered wing could be two hundred fifty per shipset, each requiring a separate static fixture. This, in turn, requires extensive space for storage, retrieval and movement of fixtures in addition to the cost arising from large numbers of fixtures. Accordingly, it would be highly desirable to provide a flexible or programmable fixture for use in assembling and fastening a family of parts. Such flexible fixture could eliminate the need and non-recurring cost of separate fixtures for each assembly, reduce the cost associated with fixture modification necessitated by assembly design changes, reduce the lead time to process new assemblies into production or introduce changes and reduce the level of skilled labor required to refer to drawings to set up parts in the fixtures and perform high-quality fastening.